Journal articles on the topic 'Cement-bound mixture'
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Skels, Peteris, Viktors Haritonovs, and Edvards Pavlovskis. "Wood Fly Ash Stabilized Road Base Layers with High Recycled Asphalt Pavement Content." Baltic Journal of Road and Bridge Engineering 16, no. 2 (June 21, 2021): 1–15. http://dx.doi.org/10.7250/bjrbe.2021-16.520.
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Wood fly ash stabilised road base layers with high recycled asphalt pavements content was studied both at the laboratory and in-situ. The original recipe was chosen based on an actual stabilised pavement base layer design with cement CEM II/B-T 42.5R but optimised using wood fly ash. The existing road base layer from gravel was mixed with dolomite aggregate and recycled asphalt pavement, adding cement and wood fly ash at different proportions. The mixture was compacted at optimal water content according to the Standard Proctor test and further conditioned. Resistance to freezing and thawing of hydraulically bound mixtures was checked after 28 days of conditioning. Even 50 cycles of freezing and thawing were used. Test results indicated wood fly ash as an effective alternative to the typically used cement for road base stabilisation, including recycled asphalt pavement material. Three hydraulically bound mixtures were chosen for test sections in the pilot project. The project includes five different sections with three different hydraulic binder recipes. The performance of each section was evaluated.
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Buczyński, Przemysław, Marek Iwański, Grzegorz Mazurek, Jakub Krasowski, and Maciej Krasowski. "Effects of Portland Cement and Polymer Powder on the Properties of Cement-Bound Road Base Mixtures." Materials 13, no. 19 (September 24, 2020): 4253. http://dx.doi.org/10.3390/ma13194253.
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This article presents the test results for the physical and mechanical properties and fracture toughness of polymer-modified hydraulically-bound mixtures (HBM) produced with Portland cement for road base layers. The modifier used was a redispersible polymer powder (RPP) based on a vinyl ethylene acetate (EVA) copolymer obtained by spray drying. A three-level full factorial design with two factors was applied to determine the contents of Portland cement and polymer powder in the cement-bound mixture (CBM). Both Portland cement and polymer powder were added at three levels: 0%, 2%, and 4%. The assessment included basic physical properties (water absorption, density, and bulk density) and mechanical properties (stiffness modulus, axial compressive strength, and indirect tensile strength) of the CBM. Particular attention was paid to the assessment of fracture toughness in the semi-circular bending test. The results of the research show that polymer powder positively influenced the mechanical properties of CBM by improving its cohesion while maintaining its stiffness. Another benefit coming from the use of polymer powder was the CBM’s increased resistance to cracking, which is the desired characteristic from the perspective of pavement durability.
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Zvonarić, Matija, Ivana Barišić, Mario Galić, and Krunoslav Minažek. "Influence of Laboratory Compaction Method on Compaction and Strength Characteristics of Unbound and Cement-Bound Mixtures." Applied Sciences 11, no. 11 (May 21, 2021): 4750. http://dx.doi.org/10.3390/app11114750.
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During road construction, granular materials for the unbound base course (UBC) and cement-bound base course (CBC) are mostly compacted by vibratory rollers. A widespread laboratory test for determining the optimal moisture content (OMC) and maximum dry density (MDD) of the mixture for installation in UBC and CBC is the Proctor test. Considering that the Proctor test does not produce any vibrations during compaction, this paper compares the Proctor test and the vibrating hammer test. The examination was conducted on UBC and CBC with varying cement content and aggregate types. All mixtures were compacted by both methods with the aim of determining the compaction and strength characteristics. The results indicated the high comparability of the two test methods for mixtures with natural aggregate in terms of MDD, OMC, density and strength characteristics (California bearing ratio (CBR) for UBC and 28-day compressive strength for CBC). For mixtures with higher cement content, the OMC difference depending on the laboratory compaction method used can be significant, so the laboratory compaction method should be chosen carefully, particularly for moisture-susceptible materials. This paper also reveals that by increasing the proportion of rubber in the mixture, the compaction and strength characteristics differ significantly due to the compaction method. Therefore, when using alternative and insufficiently researched materials, the compaction method should also be chosen carefully.
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Illyasch, Sergey, and Tetyana Tereshchenko. "Differentiation of methods for manufacturing the specimens of mixtures based on hydraulic binders." Dorogi i mosti 2021 (March 25, 2021): 129–43. http://dx.doi.org/10.36100/dorogimosti2021.23.129.
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Introduction. To the particular group of road materials that are applied by close technologies belong hydraulically bound mixtures, roller-compacted concrete and cold recycled cement bound mixtures. As it is known, the composition and also the technology of application of road materials both affect the choice of method for their specimens manufacturing. For the Ukrainian road building industry, only one method for such specimens manufacturing was implemented, but in the world-wide practices there exist a developed differentiation of said methods which considers a lot of factors. The paper is aimed on the analysis and issues to be resolved in that direction.General classification, analysis and criteria for selecting the standard methods for manufacturing the specimens of mixtures based on hydraulic binders.Taking into consideration the methods of compaction applied in various systems of standardization, the classification of methods of manufacturing of specimens of the specified types of mixtures was offered. A comparative analysis of methods of specimens manufacturing is performed taking into account the requirements for specimens, features of the procedure of selection of the mixture composition, conditions of specimens manufacturing and also mixture grading. Particular attention was paid to the choice of criteria for the manufacture of specimens of cold recycled mixtures, which, according to world practice of road construction, shall be subjected to the rheological properties testing.Conclusions.Accounting for the world-wide experience in road building industry, established in Ukrainian practice methods of manufacturing specimens of mixtures based on hydraulic binders used by close technologies need to be improved in order to:–provide a selective approach to the procedure for selecting the mixture composition;–realize the possibility for making specimens on the construction area;–ensure performing of tests accounting for the extended requirements for said mixtures.Keywords: hydraulically bound mixture; roller-compacted concrete; cold recycled mixtures; methods of specimens manufacturing; compaction methods
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Teijón-López-Zuazo, E., Á. Vega-Zamanillo, M. Á. Calzada-Pérez, and L. Juli-Gándara. "Estimation of unconfined compressive strength of cement-stabilized jabre as material upgrade on highway construction." Materiales de Construcción 70, no. 338 (May 12, 2020): 218. http://dx.doi.org/10.3989/mc.2020.09019.
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Granite rock has powerful alterations at several meters of depth. The clayed sand resulting is commonly known as jabre. This “in situ” mixture of cement-stabilized soil requires a laboratory formula. Even when the test section is correctly verified, the mechanical properties of the homogeneous mixture of jabre exhibit high degrees of dispersion. The laboratory work undertaken included particle-size analysis and screening, definition of liquid and plastic limits, compressive strength, dry density and moisture content over stabilized samples, modified Proctor, California Bearing Ratio (CBR) and the determination of the workability of the hydraulically bound mixtures. The stress resistance curve was analyzed by means of a multilinear model of unconfined compressive strength (UCS). Since practical engineering only requires UCS for 7 days, in order to gain greater knowledge of the material, other UCS transformations were used at other curing times such as 7, 14 and 28 days.
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Tataranni, Piergiorgio, Cesare Sangiorgi, Andrea Simone, Valeria Vignali, Claudio Lantieri, and Giulio Dondi. "A laboratory and field study on 100% Recycled Cement Bound Mixture for base layers." International Journal of Pavement Research and Technology 11, no. 5 (September 2018): 427–34. http://dx.doi.org/10.1016/j.ijprt.2017.11.005.
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Bulíková, Lucia, and František Kresta. "Hydraulic Road Binder with High Share of Fly Ash after Denitrification." Solid State Phenomena 292 (June 2019): 96–101. http://dx.doi.org/10.4028/www.scientific.net/ssp.292.96.
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Power plants use new technologies to reduce emissions limits. Denitrification is a process that leads to the reduction of NOx in the flue gas. However, in this process, the ammonia or urea is bound to the fly ash and it may adversely affect the properties of this secondary material and it influences its practical utilisation. In this contribution research of siliceous fly ash after denitrification by SNCR in the field of hydraulic road binders for soil treatment is described. In the last time a number of new hydraulic road binders with fly ash as their component have been prepared and used. Fly ash is used due to its pozzolan properties (siliceous FA) or hydraulic properties (calcareous FA) and low purchase price. In described case, fly ash after denitrification was used in mixture with Portland cement and cement kiln dust in ratio 60/30/10. The prepared mixture showed good properties and fulfilled requirements of the EN 13282-2: Normal hardening hydraulic road binders. These binders have to comply with the requirements determined by cement standards.
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Zhu, Qiao, Yi Chen, and Lin Hua Jiang. "Effect of Mineral Admixtures on Chloride Binding Mechanism in Concrete." Applied Mechanics and Materials 204-208 (October 2012): 3716–19. http://dx.doi.org/10.4028/www.scientific.net/amm.204-208.3716.
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The chloride binding mechanisms of different mineral admixtures under the condition of stray current and NaCl solute were researched. The electric potential titration was used to measure the content of total chloride ions and free chloride ions. The results show that using of mineral admixture could effectively inhibit the destructive action of the stray current to the stability of bound chloride ion in cement paste. Among all, the most effective mix proportion on chloride-induced corrosion is the mixture with only slag, then the double mixing of fly ash and slag, the last comes the mixture with only fly ash.
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Zvonarić, Matija, Ivana Barišić, Tihomir Dokšanović, and Martina Zagvozda. "Preliminary Research On Waste Rubber Application In Cement Bound Base Layer." IOP Conference Series: Materials Science and Engineering 1202, no. 1 (November 1, 2021): 012047. http://dx.doi.org/10.1088/1757-899x/1202/1/012047.
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Abstract Besides all the positive characteristics of cement bound courses (CBC), it has some detrimental effects on the pavement wearing courses. Due to cement hydration, this mixture is affected by shrinkage. Shrinkage induces cracks in the whole layer which along with weather conditions propagate through asphalt layers in a short period. Also, it’s stiffness negatively affects cracks propagation without providing elastic support for upper layers. As a result, roads are covered with various damages which reduces driving comfort and safety and demand new financial investments. The focus is on reducing the detrimental effect of CBC on the pavement. Nowadays, large quantities of recycled rubber can be found on the market. Wasted rubber is a large ecological problem due to its long decomposition period. On the other hand, by mechanical grinding and separation process, suitable fractions of rubber can be obtained for use in construction. Consequently, the replacement of conventional material by crumb rubber reduces the consumption of natural material and energy for its exploitation. Appropriate amounts and fractions of recycled rubber have the potential to reduce shrinkage and increase the elasticity of CBC. Within this paper, preliminary research results will be presented on the possibilities of crumb rubber implementation in CBC and its effects on mechanical characteristics. By using recycled materials in construction processes we undertake a major step in the sustainable management of natural resources.
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Prathumsuwan, Thitarat, Alfred A. Christy, and Rein Terje Thorstensen. "Hydration Chemistry of Cement Studied by Near Infrared Spectroscopy." Key Engineering Materials 765 (March 2018): 309–13. http://dx.doi.org/10.4028/www.scientific.net/kem.765.309.
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Cement is a complex mixture of inorganic compounds which mainly composed of calcium silicates and calcium aluminates. Cement is mixed with water to form concrete. During the mixing calcium silicate hydrate (CSH) and calcium hydroxide are formed. The ratio of water/cement (w/c ratio) is important to obtain a mixture that gives optimum strength to the concrete. In this work, three different cement samples were mixed with water in four different ratios, including 0.35, 0.40, 0.45 and 0.55, respectively. The hydration process of cement was investigated by using near infrared (NIR) spectroscopy over a period of 28 days. The combination frequency of OH stretching and bending of water molecules gives rise to an absorption around 5200 cm-1. This peak contains contributions of overtones from several types of water molecules in the cement. Fourth derivatives spectra of all cement samples showed three peaks in the combination band region of 5300-5100 cm-1. These peaks indicated the presence of three distinct types of water molecules in the system. First, the characteristic peak at 5260-5240 cm-1 represented the hydrogen bond between water molecules and silinol group of calcium silicates. This peak indicated the formation of CSH from hydration of cement. Furthermore, this peak experienced a slight red shift after a period of seven days indicating stronger hydrogen bonding of water molecules with silinol groups. The peak at 5130 cm-1 corresponded to hydrogen bonding between water molecules and the peak at 5165 cm-1 corresponded to hydrogen bonding between free water and bound water. The suitable w/c ratio for cement-1 is at 0.35-0.45, cement-2, and cement-3 are 0.45. In addition, real concrete sample showed two characteristic peaks at 5250 cm-1 and 5165 cm-1, demonstrating the presence of CSH and free water within concrete, respectively. Near infrared spectroscopy in combination with fourth derivative technique can be used to investigate the hydration chemistry of cement and concrete.
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Dimter, Sanja, Martina Zagvozda, Tea Tonc, and Miroslav Šimun. "Construction Of Economical Pavement Structures With Wood Ash." IOP Conference Series: Materials Science and Engineering 1202, no. 1 (November 1, 2021): 012048. http://dx.doi.org/10.1088/1757-899x/1202/1/012048.
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Abstract Stabilized mixes that are used in pavement structures are composed of aggregate bound with hydraulic binders (cement, lime) or bitumen. The most commonly used for the construction of base layers are mixes stabilized with cement. A long-standing construction practice for pavement structures was based on the use of quality granular materials for the construction of base layers. However, when designing the pavement structure and selecting materials, economy, sustainability, and environmental impact, in addition to their mechanical properties, should also be considered. Clear requirements and guidelines for sustainable development have imposed the need to explore the possibility of using non-standard materials in construction. Wood ash, which is formed as a residue from the combustion of biomass in the production of electricity and heat, is one of the newer and, in Croatia, less researched alternative materials that can be applied in construction. The paper describes compressive strength tests of mixtures of sand from the Drava River and cyclone wood ash stabilized with various contents of cement. The obtained results showed that with wood fly ash (in a content of 30 % mass.) in the stabilization mixture of sand, values of compressive strengths can be achieved within the required limits necessary for the construction of base layers of the pavement structure stabilized by a hydraulic binder.
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Tsynka, Anatolii, Sergey Illyasch, and Tetyana Tereshchenko. "СRUSHED STONE MATERIALS AND GRAVEL MATERIALS BOUND BY MINERAL BINDERS. STANDARDIZATION." Dorogi i mosti 2021, no. 24 (October 1, 2021): 28–39. http://dx.doi.org/10.36100/dorogimosti2021.24.028.
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Introduction. This paper presents the results of the standardization of requirements for granular mixtures bound by mineral binders for bases, sub-bases and top layers of road pavements used as framework for national standard «Crushed stone materials and gravel materials for the road building industry — Specifications. Part 3: The materials bound by mineral binders». Standardization. The standard covers the requirements for crushed stone-sand and sand-gravel mixtures treated with mineral binders and derived from them hardened materials as well as the requirements for source constituents. Mineral binder for the standardized type of road materials shall be selected from following main constituents: cement, slag or fly ash each separately or combinations thereof using an activator if required. Standard mixtures shall be produced in a factory or mixed in situ on the road surface. Clauses of the standard also comprise the requirements for mixtures and related hardened materials from active slag or ash-slag materials which can act as the main constituent of the mixture (aggregate) and part of the binder. Standardized mandatory characteristics include mixtures physical properties comprising grading envelopes, and mechanical properties; the obligatory sections of the standard include requirements on quality control, transporting and marking of mixtures. Conclusions. Conclusions outline main results of standardization in view of the ongoing works on processing the related European Norms as national normative documents. It is emphasized that the developed standard supplements the fundamental requirements of adapted European normative documents regarding the composition and properties of said mixtures, particularly the requirements on frost resistance. The subsequent work shall be aimed at the adaptation of national regulations on road pavement design and construction to implement the newly standardized requirements for hydraulically bound mixtures.
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Berber, Hakan, Kadriann Tamm, Mari-Liis Leinus, Rein Kuusik, Kaia Tõnsuaadu, Peeter Paaver, and Mai Uibu. "Accelerated carbonation technology granulation of industrial waste: Effects of mixture composition on product properties." Waste Management & Research 38, no. 2 (November 22, 2019): 142–55. http://dx.doi.org/10.1177/0734242x19886646.
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The use of accelerated carbonation technology in combination with a granulation process was employed to produce aggregates from a variety of industrial wastes, which included municipal solid waste incineration fly ash and air pollution control residue, oil shale ash, cement kiln dust, and quarry fines that have been produced in Estonia. Focusing mainly on the effects produced by the content of municipal solid waste incineration ash in the admixtures, the granule compositions were varied in order to tailor granule properties on the basis of CO2 uptake, strength development, leaching behaviour, microstructure, and morphology. All the steps involved in the accelerated carbonation technology granulation process, from mixing with additives to granulation and carbonation treatment, were carried out in the same apparatus – an Eirich EL1 intensive mixer/granulator. The amount of CO2 that was bound ranged from 23 to 108 kg per tonne of waste. The granules that included the optimised mixture of municipal solid waste incineration air pollution control residue, oil shale ash, cement kiln dust, and ordinary Portland cement were characterised by the highest compressive strength (4.03 MPa) and water durability for the size range of 4–10 mm. In addition, the process was found to be effective in reducing alkalinity (pH < 11.5) and immobilising heavy metals (especially zinc) and chloride. The composition and properties of the respective waste materials and mechanisms associated with the characteristics of the resulting granules were also addressed.
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Guan, Qingfeng, Jingliang Xia, Jing Wang, Faguang Leng, Yongxiang Zhou, and Changwei Cao. "Recycling Blast Furnace Ferronickel Slag as a Replacement for Paste in Mortar: Formation of Carboaluminate, Reduction of White Portland Cement, and Increase in Strength." Materials 14, no. 10 (May 20, 2021): 2687. http://dx.doi.org/10.3390/ma14102687.
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Blast furnace ferronickel slag (BFFS) is generated in the production of ferronickel alloys and is used as cement replacement in concrete or mortar. The effectivity in reducing cement consumption and improving performance are limited. By referring to the paste replacement method, this work used BFFS to replace an equal volume of the white Portland cement paste to obtain greater performance enhancement. BFFS was used with five levels of replacement (0%, 5%, 10%, 15%, 20%) and four water-to-cement ratios (0.40, 0.45, 0.50, 0.55) were designed. Fluidity, mechanical strength, hydration products, and pore structure of every mixture were measured. The results showed that the workability of the mortars decreased due to the reduced volume of water, but the 28-day compressive strength of the mortars increased, and the cement content of the mortars was also reduced by 33 wt %. The X-ray diffraction (XRD) patterns revealed that there existed a carboaluminate phase, and the presence of the ettringite was stabilized, indicating that the accumulating amount of the hydration products of the mortar increased. Furthermore, the BFFS could consume the portlandite and free water to form a higher amount of chemically bound water due to its pozzolanic activity. A high degree of hydration and a large volume of the hydration products refined the porosity of the hardened mortars, which explained the enhancement of the strength of the mortars. Compared to the cement replacement method, the paste replacement method was more effective in preparing eco-friendly mortar or concrete by recycling BFFS for reducing the cement content of the mortar while improving its strength.
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Kopecskó, Katalin, and Lilla Mlinárik. "The influence of different types of SCMs on microstructure and macroscopic properties of cementitious materials." Journal of Physics: Conference Series 2315, no. 1 (July 1, 2022): 012019. http://dx.doi.org/10.1088/1742-6596/2315/1/012019.
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Abstract In our study, the influence of different supplementary cementitious materials (SCMs) such as metakaolins, silica fume (microsilica) or filtered coal fly ash on the performance of concrete is discussed. The effects of different types and dosages of the SCMs have been investigated. Centrilit NC (MK1) and Metaver N (mk2) type metakaolins, Microsit® 20 (MS) type filtered coal fly ash or Centrilit Fume SX (SF) silica fume suspension was chosen as the replacement for the CEM I 42.5 N-SR0 sulphate resistant Portland cement. In addition to the two-component mixtures, we also examined the behaviour of the ternary blends, i.e. the combinations of SCMs. For the experiments, mortar prisms and cylindrical mortar specimens were prepared with water to binder ratio of 0.4. The paper presents the test results performed up to two years. The compressive strengths of the mixtures were examined. The most critical property of the cement-bound materials, the chloride migration coefficient of each mixture, was determined. The microstructure of the mixtures was determined by mercury intrusion porosimetry at the age of one year. Our results indicated (i) the best compressive strength was achieved for MK2 and for MK1 with combination of SF; (ii) the pore structure is much finer in the case of MK1 mixtures compared with those of MK2 or MS mixtures; (iii) the whole most frequent pore diameter interval falls into the range of medium capillaries only in case of MK1 (10 w%), for other mixtures the large capillaries are present in different extent. The SCMs greatly influence the extent of the enhancement in chloride migration coefficients with age: the less reduction was found for the mixtures of MK1, and the highest reduction was found for mixtures of MS. There is no direct function between the compressive strength, total porosity, specific surface of porosity or chloride migration coefficients.
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Raj, Shubham, Sher Mohammad, Rima Das, and Shreya Saha. "Coconut fibre-reinforced cement-stabilized rammed earth blocks." World Journal of Engineering 14, no. 3 (June 12, 2017): 208–16. http://dx.doi.org/10.1108/wje-10-2016-0101.
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Purpose This study aims to investigate the optimum proportion of coconut fibre and cement suitable for rammed earth wall construction. Coconut fibres and cement can be easily incorporated into the soil mixture which adds strength and durability to the wall. This paper highlights the salient observations from a systematic investigation on the effect of coconut fibre on the performance of stabilized rammed earth blocks. Design/methodology/approach Stabilization of soil was done by adding Ordinary Portland Cement (2.5, 5.0, 7.5 and 10.0 per cent by weight of soil), whereas coconut fibre in length about 15 mm was added (0.2, 0.4, 0.6, 0.8 and 1.0 per cent by weight of soil) as reinforcement. Thirty types of mixes were created by adding different proportions of cement and fibre to locally available soil and compacting the mix at constant compaction energy in three layers with Proctor rammer. Findings Samples were tested for compressive strength and tensile strength, and failure patterns were analysed. The use of cement and fibre increases ultimate strengths significantly up to an optimum limit of 0.8 per cent fibre content, provides a secondary benefit of keeping material bound together after failure and increases residual strength. Benefits of fibre reinforcement includes both improved ductility in comparison with raw blocks and inhibition of crack propagation after its initial formation. Originality/value After analysing the results, it is recommended to use 0.8 per cent fibre and 5-10 per cent cement by weight of soil to achieve considerable strength. This research may add a value in the areas of green and sustainable housing, waste utilization, etc.
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Wolf, Benjamin, Johannes Paule, and Andrea Kustermann. "Investigation of the influence of fine recycled sand on the setting behaviour of cement when used as supplementary cementitious material (SCM)." MATEC Web of Conferences 364 (2022): 05009. http://dx.doi.org/10.1051/matecconf/202236405009.
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The building materials industry makes a major contribution to greenhouse gases emitted each year, particularly by the cement clinker production. Therefore, the aim should be to maintain an increased part of building material from demolition sites in the material cycle. The use of the fine material (< 2mm) from demolition waste in concrete has so far proved to be problematic due to the increased water demand and loss of compressive strength. One approach is the use of recycled concrete powder (RCP) as supplementary cementitious material (SCM). Demolition material used in this study has been obtained from discarded railroad sleepers and pre-crushed as sand (< 4 mm). The recycled sand was subjected to a mechanical and thermal activation process before use, then was ground to a particle size <63 μm and then fired at 4 different temperatures (750°C, 800°C, 850°C, 900°C). The aim was to convert parts of the hydrated C-S-H structure back into reactive silicate phases through firing process. They can contribute again to the hydration process when used as supplementary cementitious material. The ground and thermally treated material - called SCM - wasexamined for their physical and chemical properties. Subsequently, 10 and 20 Vol.-% were replaced by the SCM in a binder mixture, respectively. In a first step, the different water demand of the binders was documented. Ultrasonic methods were used to investigate the stiffening and setting behaviour of the binders. The decisive factor here was the proportion of chemically bound water in the binder mixtures. Finally, the mechanical properties of the binders were investigated in mortar tests. Acceptable compressive strengths were achieved compared to the reference mortar (mortar mixture without cement substitution). At first glance, it seems possible to use it as an SCM.
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Cui, Ying, and Zhongsheng Tan. "Experimental Study of High Performance Synchronous Grouting Materials Prepared with Clay." Materials 14, no. 6 (March 11, 2021): 1362. http://dx.doi.org/10.3390/ma14061362.
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Shield construction discharges a large amount of soil and muck. The utilization of discharged soil of shield always has high energy consumption and a low utilization rate. Meanwhile, synchronous grouting is a key process for shield tunneling. The current studies show that the synchronous grouting materials applied now generally have the problem of mismatching among filling property, fluidity, and consolidation strength. In order to study the feasibility of using the excavated soil produced by shield construction in clay stratum as synchronous grouting material, high performance synchronous grouting material was studied by taking red clay as an example, modified by epoxy resin. The fluidity, stability, and strength were measured to evaluate performance of the grout. Material test results show that the addition of waterborne epoxy resin decreases density, improves the stability, the rate of stone, and the toughness of the grouting concretion. Finally, X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM) were measured to analyze the cementitious mechanism of the grout, test results demonstrated that cement hydration and curing reaction of epoxy resin happened in the grout, the formed polymer film filled the voids in the mixture and effectively bound cement hydration gel and clay particles together.
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Lin, Run-Sheng, Xiao-Yong Wang, Han-Seung Lee, and Hyeong-Kyu Cho. "Hydration and Microstructure of Cement Pastes with Calcined Hwangtoh Clay." Materials 12, no. 3 (February 1, 2019): 458. http://dx.doi.org/10.3390/ma12030458.
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Calcined Hwangtoh (HT) clay is a very promising supplementary cementitious material (SCM). In this work, the development of the mechanical properties and microstructures of HT-blended cement paste was studied after substituting the binder with HT powder calcined at 800 °C. The water-to-binder (w/b) ratios of the paste used were 0.2 and 0.5, and the quantities of HT powder added to the mixture were 0, 10, and 20%. The compressive strength test indicates that the addition of the HT powder increases the compressive strength of the paste after seven days of curing, and the highest compressive strength is obtained with the 10% HT substitution, regardless of whether the w/b ratio is 0.5 or 0.2. X-ray fluorescence (XRF), X-ray diffraction (XRD), inductively coupled plasma mass spectrometry (ICP-MS), isothermal calorimetry, thermogravimetric analysis (TGA), and attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) analysis show that the HT powder not only has a physical effect (i.e., nucleation effect and dilution effect) on cement hydration but also has a chemical effect (i.e., chemical reaction of HT). The results of scanning electron microscopy (SEM) and mercury intrusion porosimetry (MIP) analysis show that the paste has more ettringite during the early stage, and the microstructure is refined after the addition of the HT powder. In addition, the relationships between chemically bound water, hydration heat, and compressive strength are presented.
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Khayrutdinova, D. R., V. V. Smirnov, O. S. Antonova, M. A. Goldberg, S. V. Smirnov, T. O. Obolkina, and S. M. Barinov. "The influence of sodium and potassium doping effect on phase formation in calcium sulphate synthesis." Доклады Академии наук 489, no. 1 (November 10, 2019): 49–52. http://dx.doi.org/10.31857/s0869-5652489149-52.
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Calcium sulphate-based materials were synthesized and investigated, in which Ca2+ cations were substituted for Na+ or K+ cations in an amount of 5, 10 and 20 mol.%. With the introduction of Na+, materials with the structure semi-aqueous and two-water calcium sulfate were obtained, with the introduction of potassium, a mixture of calcium sulfates with different content of chemically bound water and sulfates were obtained, in which potassium cations are forming compounds with different Ca/K ratio. Doping of calcium sulphate with potassium and sodium cations led to an increase in the solubility of materials: for sodium-containing ones by 1,2 times, for potassium-containing ones by 3-4 times. The developed materials are promising for use in medicine for filling bone tissue defects, and can also be used as a cement matrix for targeted drug delivery.
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Li, Shuai, Yulin Zhang, Ru Feng, Haoxuan Yu, Jilong Pan, and Jiwei Bian. "Environmental Safety Analysis of Red Mud-Based Cemented Backfill on Groundwater." International Journal of Environmental Research and Public Health 18, no. 15 (July 30, 2021): 8094. http://dx.doi.org/10.3390/ijerph18158094.
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As one of the main industrial solid wastes, there are a large number of free alkaloids, chemically bound alkaloids, fluoride, and heavy metal ions in Bayer process red mud (BRM), which are difficult to remove and easily pollute groundwater as a result of open storage. In order to realize the large-scale industrial application of BRM as a backfilling aggregate for underground mining and simultaneously avoid polluting groundwater, the material characteristics of BRM were analyzed through physical, mechanical, and chemical composition tests. The optimum cement–sand ratio and solid mass concentration of the backfilling were obtained based on several mixture proportion tests. According to the results of bleeding, soaking, and toxic leaching experiments, the fuzzy comprehensive evaluation method was used to evaluate the environmental impact of BRM on groundwater. The results show that chemically bound alkaloids that remained in BRM reacted with Ca2+ in PO 42.5 cement, slowed down the solidification speed, and reduced the early strength of red mud-based cemented backfill (RMCB). The hydration products in RMCB, such as AFT and C-S-H gel, had significant encapsulation, solidification, and precipitation inhibition effects on contaminants, which could reduce the contents of inorganic contaminants in soaking water by 26.8% to 93.8% and the leaching of toxic heavy metal ions by 57.1% to 73.3%. As shown by the results of the fuzzy comprehensive evaluation, the degree of pollution of the RMCB in bleeding water belonged to a medium grade Ⅲ, while that in the soaking water belonged to a low grade II. The bleeding water was diluted by 50–100 times to reach grade I after flowing into the water sump and could be totally recycled for drilling and backfilling, thus causing negligible effects on the groundwater environment.
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Drljaca, Dijana, Ljiljana Vukic, Dajana Dragic, Aleksandra Borkovic, Tatjana Botic, Pero Dugic, Sasa Papuga, et al. "Leaching of heavy metals from wood biomass ash, before and after binding in cement composite." Journal of the Serbian Chemical Society, no. 00 (2022): 54. http://dx.doi.org/10.2298/jsc220217054d.
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Wood ash is a complex mixture of inorganic and organic compounds. It is heterogeneous in composition, which can vary considerably. Ash is mainly disposed of in landfills, which poses a risk for air, soil and groundwater contamination by trace elements. In order for wood biomass ash to be used as a secondary raw material, it is necessary to perform leaching tests, to determine which microelements it contains, and which of them could be released into the environment during the ash disposal. Sequential extraction showed that in the exchangeable and carbonate fraction, the most volatile metals As, Cd, Zn and Pb are released the most from the ash of deciduous trees, while the leaching of ash from coniferous trees is significantly lower. The evaluation of risk assessment code (RAC) for the tested biomass ash samples, indicates that Pb is a high-risk leaching element due to its condensation on the ash particles. By performing TCLP (Toxicity Characteristic Leaching Procedure) and SPLP (Synthetic Precipitation Leaching Procedure) tests, it was established that the released concentrations of tested metals are below the maximum allowable concentration, given by the Regulation. The leaching tests of composites, prepared from wood ash in combination with cement, indicate that the leaching of ash is reduced to a minimum, and that all heavy metals are bound in a cement matrix, which indicates the possibility of using wood ash for construction purposes.
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Diamanti, Maria Vittoria, Cristina Tedeschi, Mariagiovanna Taccia, Giangiacomo Torri, Nicolò Massironi, Chiara Tognoli, and Elena Vismara. "Suspended Multifunctional Nanocellulose as Additive for Mortars." Nanomaterials 12, no. 7 (March 26, 2022): 1093. http://dx.doi.org/10.3390/nano12071093.
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Cellulose derivatives have found significant applications in composite materials, mainly because of the increased mechanical performance they ensure. When added to cement-based materials, either in the form of nanocrystals, nanofibrils or micro/nanofibers, cellulose acts on the mixture with fresh and hardened properties, affecting rheology, shrinkage, hydration, and the resulting mechanical properties, microstructure, and durability. Commercial cotton wool was selected as starting material to produce multifunctional nanocelluloses to test as additives for mortars. Cotton wool was oxidized to oxidized nanocellulose (ONC), a charged nanocellulose capable of electrostatic interaction, merging cellulose and nanoparticles properties. Oxidized nanocellulose (ONC) was further functionalized by a radical-based mechanism with glycidyl methacrylate (GMA) and with a mixture of GMA and the crosslinking agent ethylene glycol dimethacrylate (EGDMA) affording ONC-GMA and ONC-GMA-EGDMA, both multifunctional-charged nanocellulose merging cellulose and bound acrylates properties. In this work, only ONC was found to be properly suitable for suspension and addition to a commercial mortar to assess the variation in mechanical properties and water-mortar interactions as a consequence of the modified microstructure obtained. The addition of oxidized nanocellulose caused an alteration of mortar porosity, with a decreased percentage of porosity and pore size distribution shifted towards smaller pores, with a consequent increase in compressive resistance, decrease in water absorption coefficient, and increased percentage of micropores present in the material, indicating a potential improvement in mortar durability.
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Cheng, An, Wei-Ting Lin, Lukáš Fiala, Petr Hotěk, Sao-Jeng Chao, and Hui-Mi Hsu. "Electrical resistance and self-sensing properties of pressure-sensitive materials with graphite filler in Kuralon fiber concrete." Materials Science-Poland 40, no. 2 (August 1, 2022): 223–39. http://dx.doi.org/10.2478/msp-2022-0023.
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Abstract This study aimed to investigate conductivity behavior of concrete containing graphite and its sensitivity to the effects of pressure. Graphite powder was added to concrete to replace partial cement (4 wt.%, 8 wt.%, 12 wt.%, and 16 wt.%) as conductive fillers with a water-to-cementitious ratio of 0.45. Specimens with 0.5 vol.% Kuralon fibers were treated to enhance the performance of self-sensing properties to investigate the influence of graphite and fiber contents on electrical resistivities. The relationship between the axial load and changes in resistivity was determined using cyclic loading tests, indicating the existence and development of internal cracking in concrete. The results indicated that the compressive strength presented a linear decline proportional to the addition of graphite. Specimens with 8% graphite reached the lower bound of self-sensing properties, and with an increase in the amount of graphite, resistivity gradually decreased. In the cyclic loading tests, specimens containing >8% graphite were able to better reflect the relationship between loading and resistivity. Kuralon fibers in concrete had further improvement in resistance and self-sensing properties. In inclusion, the mixture with 8% graphite provided the best self-sensing properties to warn for preventing the effects of cracking, as well as achieved better mechanical properties.
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Sakhare, Akshay, Hafsa Farooq, Sanjay Nimbalkar, and Goudappa R. Dodagoudar. "Dynamic Behavior of the Transition Zone of an Integral Abutment Bridge." Sustainability 14, no. 7 (March 30, 2022): 4118. http://dx.doi.org/10.3390/su14074118.
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Weaker sections of a railway track, such as the approach sections, are prone to differential settlement under the action of repeated train loads. The railway tracks degrade more quickly at a critical section adjacent to a traditional rail bridge because of progressive deterioration. Opting for an integral abutment instead of a traditional bridge is gaining importance due to its improved performance in terms of track stiffness and reduced settlement. It is essential to understand such issues with the appropriate methodologies. This study investigates the behavior of an integral abutment bridge with the transition zone subjected to train loading. Generally, the transition zone is a two-part wedge section consisting of unbound granular material and cement bound mixture. A field monitored traditional abutment bridge system is used to validate the developed two-dimensional Finite Element (FE) model. The model is further developed to simulate the dynamic behavior of the transition zone against the varying speeds of the train. The parametric study is performed on the transition zone by varying its geometric configurations and considering different materials for the backfill. The results indicate that the trapezoidal approach slab influences the track displacement significantly. The transition zone thickness and material properties of the backfill have a greater effect on the overall track response. Based on the results, the stable transition zones are identified to cater to the gradual stiffness variation during train–track interaction.
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Asrullah, Asrullah, Diawarman Diawarman, Rita Anggrainy, and Kamal Afif. "ANALISA KUAT TEKAN BETON Fc’25 MPa DENGAN PENAMBAHAN ABU BATU DAN SEMEN MORTAR UTAMA TYPE 400." Jurnal Teknik Sipil 11, no. 2 (January 9, 2022): 60–66. http://dx.doi.org/10.36546/tekniksipil.v11i2.517.
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Secara sederhana, beton dibentuk oleh pengerasan campuran antara semen, air, agregat halus (pasir), dan agregat kasar (batu pecah atau kerikil). Kadang-kadang ditambah bahan lain untuk memperbaiki kualitas beton. Perkembangan sekarang ini, beton merupakan bahan yang paling banyak dipakai pada pembangunan dalam bidang teknik sipil, baik pada bangunan gedung, jembatan, bendung, maupun konstruksi lain. Sifat dari bahan beton, yaitu sangat kuat untuk menahan tekan, tetapi tidak kuat (lemah) untuk menahan tarik. Metode yang digunakan dala desain campuran beton menggunakan SNI 03-2834-2000. Penelitian ini dilakukan eksperimen di laboratorium. Tujuan dari penelitian ini untuk mengetahui nilai kuat tekan beton normal, nilai kuat tekan beton dengan penambahan abu batu, penambahan semen mortar utama type 400 dan kombinasi penambahan abu batu dan semen mortar utama type 400. Nilai kuat tekan beton direncanakan standar 25 MPa. Kesimpulan yang dihasilkan adalah nilai kuat tekan beton normal sebesar 25,16 MPa, kuat tekan beton terbesar dengan penambahan abu batu 6 % sebesar 26,49 MPa, kuat tekan beton terbesar dengan penambahan semen mortar utama type 400 6% sebesar 27,57 MPa dan kuat tekan beton dengan kombinasi penambahan abu batu dan semen mortar utama type 400 6% sebesar 27,97 MPa. Sedangkan model hubungan regresi linier sederhana mempunyai hubungan yang kaut antara variabel bebas (X) dengan variaber erikat (Y) dengan koefisien determinasinya (R) lebih besar dari 0,950 untuk seluruh nilai kuat tekan.
In simple terms, concrete is formed by hardening a mixture of cement, water, fine aggregate (sand), and coarse aggregate (crushed stone or gravel). Sometimes other ingredients are added to improve the quality of the concrete. Current developments, concrete is the most widely used material in construction in the field of civil engineering, both in buildings, bridges, weirs, and other constructions. The nature of the concrete material, which is very strong to withstand compression, but not strong (weak) to withstand tension. The method used in the design of concrete mix using SNI 03-2834-2000. This research was conducted experimentally in the laboratory. The purpose of this study was to determine the value of the compressive strength of normal concrete, the value of the compressive strength of concrete with the addition of stone ash, the addition of the main cement mortar type 400 and the combination of adding stone ash and the main cement mortar type 400. The compressive strength value of the concrete is planned to be 25 MPa standard. The conclusion is that the compressive strength of normal concrete is 25.16 MPa, the greatest compressive strength of concrete with the addition of 6% stone ash is 26.49 MPa, the greatest compressive strength of concrete with the addition of cement mortar type 400 6% is 27.57 MPa and The compressive strength of concrete with a combination of the addition of stone ash and the main cement mortar type 400 6% is 27.97 MPa. While the simple linear regression model has a strong relationship between the independent variable (X) and the bound variable (Y) with the coefficient of determination (R2) greater than 0.950 for all compressive strength values.
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Santana, Teresa, João Gonçalves, Fernando Pinho, and Rui Micaelo. "Effects of the Ratio of Porosity to Volumetric Cement Content on the Unconfined Compressive Strength of Cement Bound Fine Grained Soils." Infrastructures 6, no. 7 (June 26, 2021): 96. http://dx.doi.org/10.3390/infrastructures6070096.
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This paper presents an experimental investigation into the effects of porosity, dry density and cement content on the unconfined compressive strength and modulus of elasticity of cement-bound soil mixtures. A clayey sand was used with two different proportions of type IV Portland cement, 10% and 14% of the dry mass of the soil. Specimens were moulded with the same water content but using four different compaction efforts, corresponding to four different dry densities. Unconfined compression testing was conducted at seven days of curing time on unsoaked samples. The results showed that the compressive strength increased with the increase in cement content and with the decrease in porosity. From the experimental data, a unique relationship was found between the unconfined compressive strength and the ratio of porosity to volumetric cement content for all the mixtures and compaction efforts tested. The equation developed demonstrates that it is possible to estimate the amount of cement and the dry density to achieve a certain level of unconfined compressive strength. A normalized general equation was also found to fit other authors’ results for similar soils mixed with cement. From this, a cement-bound soil model was proposed for the development of a mixing design procedure for different soils.
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Atmadi, Tony Prasanto. "STUDI UJI KUAT TEKAN DAN SERAPAN AIR PADA BATA BETON BERLUBANG DENGAN BAHAN IKAT KAPUR DAN FLY ASH." Sains & Teknologi 3, no. 3 (October 21, 2019): 12. http://dx.doi.org/10.24123/jst.v3i3.2286.
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Along with population growth from year to year increase in positive correlation with housing needs. Various innovative building materials necessary to provide the public an opportunity to select materials according to their needs and abilities. One of the innovations that can be developed is the use of hollow concrete bricks as building material for walls using a different belt materials. In Indonesia, many local materials that can be used as building material for the mixed stacking hollow concrete blocks strapped him in particular materials. One of the alternative tie material can be used to reduce pamakaian Portland cement is fly ash. Innovations that can be done is making concrete hollow brick with limestone belt materials and fly ash, because the material can theoretically be bound material using the reaction mechanism pozolan-lime. Mixture composition variation between the fly ash, lime, and sand as the material collated hollow concrete blocks used in this study, respectively - are part (in weight units) 0:1:6; 0,5:1:6; 1:1:6 ; 1,3:1:6; 1,4:1:6; 1,5:1:6; 1,6:1:6; and 1,8:1:6. The parameters examined in this study include stacking the material characteristics of concrete hollow bricks, the sand gradation testing, the weight of sand, mud, sand content, conservation of sand grains, and the gradation of fly ash; strong press penyususun concrete brick mortar holes; strong press and the value of water absorption hollow concrete brick with limestone belt materials and fly ash. Hollow concrete brick testing performed three times, ie at the age of 14 days, 21 days, and 28 days. From the research results collated material characteristics of concrete hollow bricks show that gradations of sand used in Badean in zone 1, ie coarse sand, the average density - average 2.567 for Badean sand, mud content of the average - Badean sand flat 2.08% for <5% ,, conservation of grain using Na2SO4 for 5.03% <12% and conservation of grains using MgSO4 for 6.30% <10%. From the findings of conventional hollow concrete blocks with a mixture of composition 1 PC: 15 Ps for a strong test of hollow concrete brick press shows that a strong press for the optimum of 12.69 kg/cm2. And to strongly press the test hole with concrete blocks tied materials and lime fly ash showed that a strong press and the optimum occurs at the composition 1.4 Fa: 1 Kp: 6 Psr, which is 11.54 kg/cm2 at 14 days; 12.44 kg / cm2 at the age of 21 days, and 13.33 kg/cm2 at the age of 28 days. For the water absorption value of hollow concrete blocks shows that more and more pasta, then the value of water absorption decreased. Largest water absorption occurs in the variation of composition 0 Fa: 1 Kp: 6 Psr ie 5.13%, and the value of the smallest water absorption occurs at 1.8 composition variations Fa: 1 Kp: 6 Psr ie 0.05%.
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Pasetto, Marco, and Nicola Baldo. "RE-USE OF INDUSTRIAL WASTES IN CEMENT BOUND MIXTURES FOR ROAD CONSTRUCTION." Environmental Engineering and Management Journal 17, no. 2 (2018): 417–26. http://dx.doi.org/10.30638/eemj.2018.042.
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Topoliński, Szymon, Aleksandra Gorączko, Ahmet Beycioğlu, and Baki Bagriaçık. "Application of Waste Rock Dust in Cement Binding Mixtures Used in Roadway." IOP Conference Series: Materials Science and Engineering 1203, no. 3 (November 1, 2021): 032031. http://dx.doi.org/10.1088/1757-899x/1203/3/032031.
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Abstract The article contains the results of research on the effect of waste rock dust on the properties of cement-bound mixtures. Gabbro-limestone dust with a significant proportion of active silica and calcium carbonate was used for the tests. The results of strength tests after 28 days of maturation with a variable proportion of cement (3%, 5%, 7%) and rock dust (0%, 10%, 20%) are presented. The stabilized aggregate was fine sand. The obtained results did not show the expected strength and frost resistance of the tested samples. The analysis of the results shows that the addition of rock dust is not applicable in dusty soils.
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Safdar, Muhammad, Tim Newson, Colin Schmidt, Kenichi Sato, Takuro Fujikawa, and Faheem Shah. "Effect of Fiber and Cement Additives on the Small-Strain Stiffness Behavior of Toyoura Sand." Sustainability 12, no. 24 (December 15, 2020): 10468. http://dx.doi.org/10.3390/su122410468.
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The disposal of 2011 Japan earthquake waste has become an important issue in Japan and it is not realistic or economical to send all of these wastes to landfill sites, due to limited space, high costs, and related environmental issues. In sustainable geotechnical applications, mixing of the separated soils from disaster wastes with additives (e.g., cement and fiber) is required to improve their strength and stiffness characteristics. In this study, monotonic triaxial drained compression tests are performed on medium dense specimens of Toyoura sand-cement-fiber mixtures with different percentages of fiber and cement (e.g., 0–3%) additives. The experimental results indicate that behavior of the mixtures is significantly affected by the concentration of fiber and cement additives. Based on a comprehensive set of test results, modifications to the series of equations were developed that can be used to evaluate the shear modulus and mobilized stress curves at small-strain levels. The experimental results and model comparison show that the elastic threshold strain (γe), reference strain (γr), increases with fiber and cement additives. In addition, the range of curvature parameter, from 0.88 to 1.0, provides a good comparison with the results of small-strain measurements. Overall, the comparison of the results and model shows that the small-strain measurements obtained using local strain transducers fall within the range of model upper and lower bound curves. The results of the unreinforced, fiber, and cemented sand shows a close agreement with the model mean curve, but fiber-reinforced cemented sand shows a good comparison with model upper bound.
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Ho, Lanh Si, Kenichiro Nakarai, Kenta Eguchi, Takashi Sasaki, and Minoru Morioka. "Strength development of cement-treated sand using different cement types cured at different temperatures." MATEC Web of Conferences 195 (2018): 01006. http://dx.doi.org/10.1051/matecconf/201819501006.
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This study aimed to investigate the strength development of cement-treated sand using different cement types: ordinary Portland cement (OPC), high early strength Portland cement (HPC), and moderate heat Portland cement (MPC) cured at different temperatures. The cementtreated sand specimens were prepared with 8% of cement content and cured under sealed conditions at 20οC and 40οC, and mortar specimens were also prepared for reference. The results showed that the compressive strength of cement-treated sand increased in order of MPC, OPC, and HPC under high curing temperatures. It was interesting that the compressive strength of the specimens using HPC was much larger than that of the specimen using OPC and MPC under 20οC due to the larger amount of chemically bound water. Additionally, it was revealed that under high curing temperatures, the pozzolanic reaction was accelerated in the cement-treated sand; this may be caused by the high proportions of sand in the mixtures.
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Crucho, João, Luís Picado-Santos, and José Neves. "Mechanical Performance of Cement Bound Granular Mixtures Using Recycled Aggregate and Coconut Fiber." Applied Sciences 12, no. 4 (February 12, 2022): 1936. http://dx.doi.org/10.3390/app12041936.
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Construction and demolition waste (CDW) and coconut husk are frequently discharged into landfills, creating an environmental problem. However, the CDW can be used to obtain good-quality recycled aggregates (RA), and the coconut husk can be processed into coconut fiber (CF). These materials can be used in the construction of cement bound granular mixtures (CBGM) to be applied as base and sub-base layers of road pavements. Such a large-scale application would bring value to these materials and reduce the extraction of non-renewable natural resources. In this work, the mechanical performance of CBGM with RA and CF reinforcement was evaluated and compared with a conventional CBGM with natural aggregate (NA). The mechanical performance was assessed through the immediate bearing index (IBI), unconfined compressive strength (UCS), indirect tensile strength (ITS), and flexural strength (FLS) tests. The results of the experimental program allow the conclusion that the CBGM with RA present similar performance to the CBGM with NA. Furthermore, the use of CF effectively reinforced the integrity of the CBGM specimens at post-test, indicating potential gains in durability after cracking occurrence.
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Stulajterova, Radoslava, Lubomir Medvecky, Maria Giretova, Tibor Sopcak, Lenka Luptakova, Radovan Bures, and Eva Szekiova. "Characterization of Tetracalcium Phosphate/Monetite Biocement Modified by Magnesium Pyrophosphate." Materials 15, no. 7 (March 31, 2022): 2586. http://dx.doi.org/10.3390/ma15072586.
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Magnesium pyrophosphate modified tetracalcium phosphate/monetite cement mixtures (MgTTCPM) were prepared by simple mechanical homogenization of compounds in a ball mill. The MgP2O7 was chosen due to the suitable setting properties of the final cements, in contrast to cements with the addition of amorphous (Ca, Mg) CO3 or newberite, which significantly extended the setting time even in small amounts (corresponding ~to 1 wt% of Mg in final cements). The results showed the gradual dissolution of the same amount of Mg2P2O7 phase, regardless of its content in the cement mixtures, and the refinement of formed HAP nanoparticles, which were joined into weakly and mutually bound spherical agglomerates. The compressive strength of composite cements was reduced to 14 MPa and the setting time was 5–10 min depending on the composition. Cytotoxicity of cements or their extracts was not detected and increased proliferative activity of mesenchymal stem cells with upregulation of osteopontin and osteonectin genes was verified in cells cultured for 7 and 15 days in cement extracts. The above facts, including insignificant changes in the pH of simulated body fluid solution and mechanical strength close to cancellous bone, indicate that MgTTCPM cement mixtures could be suitable biomaterials for use in the treatment of bone defects.
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Alekseeva, Anna V., and Olga N. Savostikova. "Problems of the safe use of modern cement materials in the practice of drinking water supply." Hygiene and sanitation 101, no. 12 (January 12, 2023): 1458–63. http://dx.doi.org/10.47470/0016-9900-2022-101-12-1458-1463.
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Introduction. Recently, there have been increasing changes in the technology of preparation of cement mixtures and concrete, the use of new components in their composition, since traditional materials are not quite suitable for the construction of hydraulic structures, including the internal coating of pipes and drinking water tanks. However, in addition to improving the characteristics of cement mixtures, additives can have a negative impact on the environment and human health by leaching out of cement into drinking water. The definition of only the main components specified in the “Universal sanitary-epidemiological and hygienic requirements for goods subject to sanitary-epidemiological supervision (control)” (hereinafter - the Universal Requirements) does not provide complete information about the chemical safety of cement materials during the hygienic assessment. Materials and methods. There were studied eleven samples of cement mixtures from various manufacturers repaired of reinforced concrete products and structures of general and special purpose, including those in contact with drinking water, and used for the sanitation of the internal surfaces of steel pipelines (including hot water supply systems) and repair and restoration work. The evaluation of samples was carried out taking into account Universal requirements, and indicators that are not mandatory for the evaluation of these materials were investigated. Results. Hygienic assessment of cement mixtures showed lithium to be detected in some extracts in concentrations from 20 mg/L to 0.18 mg/L, which is 666 times higher than its maximum permissible concentration - 0.03 mg/L. Also, two samples showed a slight excess of the permissible chromium concentration - 0.065 mg/L and 0.09 mg/L (MPC < 0.05). Iron and zinc in insignificant concentrations were found in aqueous extracts; in one of the samples a 2-fold excess of the manganese concentration was observed. One water extract contains silicates at a concentration of 34.24 mg/L, which exceeds their permissible levels in drinking water. The analysis also identified a number of organic compounds related to oxygen-containing compounds (alcohols, phenol derivatives, ketones, esters, phthalates), for most of which no MPC has been established. Limitations. The study was carried out on eleven samples of cement mixtures under standard conditions: infusion in model media for 30 days at room temperature in the ratio: 1 cm2 of the sample surface to 1 cm3 of water. Sampling was carried out on the Days 1, 3, 5, 10, 20 and 30 of research, without changing the test water. It is necessary to conduct similar studies under experimental conditions close to the operating conditions of these materials. Conclusion. Assessing the efficiency of migration from cement-bound materials, it is necessary to take into account their capillary-porous structure on the one hand and the ability to improve the coating properties over time by converting calcium hydroxide present in freshly applied cladding into denser calcium bicarbonate. The migration of chemicals from cement-bound material is to be evaluated by taking into account the specific conditions of their use in the practice of drinking water supply, and the assessment of the additives introduced should be carried out on test cement samples, since it is impossible to theoretically calculate the migration rate of the components from the finished material.
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Farhan, Ahmed Hilal, Andrew Robert Dawson, and Nicholas Howard Thom. "Characterization of rubberized cement bound aggregate mixtures using indirect tensile testing and fractal analysis." Construction and Building Materials 105 (February 2016): 94–102. http://dx.doi.org/10.1016/j.conbuildmat.2015.12.018.
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Choorackal, Eldho, Pier Paolo Riviera, and Ezio Santagata. "Mix design and mechanical characterization of self-compacting cement-bound mixtures for paving applications." Construction and Building Materials 229 (December 2019): 116894. http://dx.doi.org/10.1016/j.conbuildmat.2019.116894.
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Barabash, І. V., I. N. Babiy, and K. O. Streltsov. "INTENSIVE SEPARATE TECHNOLOGY AND ITS INFLUENCE ON THE PROPERTIES OF CEMENT-WATER COMPOSITIONS, SOLUTIONS AND CONCRETES ON THEIR BASIS." Modern construction and architecture, no. 2 (December 28, 2022): 44–51. http://dx.doi.org/10.31650/2786-6696-2022-2-44-51.
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The article reviews the issues related to the mechanical activation of Portland cement in the separate technology of the production of concrete mixtures in the production of concrete and reinforced concrete products. Usually, an essential characteristic of composite building materials based on Portland cement and its varieties used in building processes is their rapid setting of strength. Therefore, scientific researches related to the development of technologies aimed at the intensification of cement hydration processes and the growth of the speed of concrete strength gaining are relevant. The work presents the main technological processes during the production of concrete mixtures using intensive separate technology. The usage of this technology, particularly, makes it possible to significantly increase the reversibility of forms due to a more intense concrete strength gaining on mechanically activated Portland cement, especially during the early stages of hardening. The need to include mineral filler in the form of ground quartz sand during the preparation of the cement-water composition in a high-speed mixer is founded. It was experimentally discovered that the rapid mixing of the cement-water composition in the presence of a C-3 superplasticizer causes a sharp decrease in its effective viscosity, which positively affects the reduction of the water content of concrete mixtures of the required ease of workability. The mechanical activation of Portland cement causes an increase in the amount of chemically bound water in vintage-age cement stone from 13.1% to 17.9%, which means more than 36% compared to the control. It was established that with the same amount of binder, the strength of the concrete on activated Portland cement on the first twenty-four hours of hardening is 1.8...2 times higher compared to the concrete of similar composition, the binder of which was not activated. Over time, the effect of activation on the concrete strength decreases a little, but even at 28 days, the compressive strength of concrete on the activated binder is 25…30% higher compared to the control.
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Kraszewski, Cezary, Leszek Rafalski, and Beata Gajewska. "Effect of Compaction Ratio on Mechanical Properties of Low-Strength Hydraulically Bound Mixtures for Road Engineering." Materials 15, no. 4 (February 19, 2022): 1561. http://dx.doi.org/10.3390/ma15041561.
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Road layers should be properly compacted to obtain an adequate bearing capacity and durability. Both the unbound and hydraulically bound mixtures used in the layers require compaction. After compaction and hardening, soil mixed with a binder acquires mechanical features that unbound soil lacks, including tensile strength (Rit) and unconfined compressive strength (Rc). The effect of the compaction ratio (DPr) of the low-strength cement-stabilised soils on these features has rarely been investigated. This study investigates the influence of the compaction ratio on the mechanical properties of hardened, stabilised mixtures of medium-grained sand with 5%, 6.5%, and 8% Portland cement. Cement–soil stabilisation tests showed that compressive strength depends exponentially on the compaction ratio, whereas tensile strength and the stiffness modulus depend linearly on the compaction ratio. For tensile strength and the dynamic stiffness modulus, the effect is not statistically significant, and the usual practice of ignoring compaction dependence is justified. For compressive strength, however, the effect is significant, especially when DPr = 98–100%. When the values of Rc and Rit strengths at various DPr were normalised by those at 100%, it was found that mixtures with higher strengths are the least resistant to changes in the compaction ratio. Knowing the percentage by which the value of a given parameter changes with compaction can be extremely valuable in engineering practice.
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Pasetto, Marco, and Nicola Baldo. "Recycling of waste aggregate in cement bound mixtures for road pavement bases and sub-bases." Construction and Building Materials 108 (April 2016): 112–18. http://dx.doi.org/10.1016/j.conbuildmat.2016.01.023.
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Lin, Run-Sheng, Xiao-Yong Wang, and Gui-Yu Zhang. "Effects of Quartz Powder on the Microstructure and Key Properties of Cement Paste." Sustainability 10, no. 10 (September 20, 2018): 3369. http://dx.doi.org/10.3390/su10103369.
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This paper compares the effects of the water-to-binder (w/b) ratio and quartz contents on the properties of cement–quartz paste. The w/b ratios of the paste mixtures specimens are 0.5 and 0.2, and the quartz powder contents are 0, 10, and 20%. At the age of 1, 3, 7, and 28 days, compressive strength test, X-ray fluorescence (XRF) spectroscopy, X-ray diffraction (XRD), mercury intrusion porosimetry (MIP), scanning electron microscopy (SEM), isothermal calorimetry, and thermogravimetric (TG) analysis were performed. The experimental results show that the quartz powder mainly has the dilution effect and crystal nucleation effect on cement hydration, and the addition of quartz powder does not change the type of hydration product. The effect of quartz powder on cement hydration is closely related to the w/b ratio. In the case of a low w/b ratio of 0.2, the addition of quartz powder did not impair the compressive strength of paste. For different w/b ratios (0.5 and 0.2) and various quartz powder contents (0, 10, and 20%) at different ages (1, 3, 7, and 28 days), there is a uniform linear relationship between strength and porosity. Similarly, there is a uniform linear relationship between chemically bound water and calcium hydroxide, between heat of hydration and compressive strength, and between chemically bound water and compressive strength. At the same time, the effect of the partial replacement of cement by quartz powder on sustainability is considered in this paper.
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Reiterman, Pavel, Ondřej Holčapek, Ondřej Zobal, and Martin Keppert. "Freeze-Thaw Resistance of Cement Screed with Various Supplementary Cementitious Materials." REVIEWS ON ADVANCED MATERIALS SCIENCE 58, no. 1 (April 1, 2019): 66–74. http://dx.doi.org/10.1515/rams-2019-0006.
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Abstract This paper describes a study of the effect of partial replacement of ordinary Portland cement (OPC) by various mineral additives in the screed mixtures. Ceramic powder, blast furnace slag and fly ash were gradually employed in increments of 12.5 wt.% up to 50 wt.% to replace OPC. The mixtures were designed to a constant consistency. The influence of mineral additives was evaluated in terms of the air content in the fresh mixtures, the compressive strength, the flexural strength and the freeze-thaw resistance and using non-destructive measurements after 28 and 90 days. The accompanied paste sampleswere analysed using thermogravimetry to monitor the hydration process by means of total bound water content. The decrease in the mechanical properties and the frost resistance of the mixtures with the mineral additives were recorded, because of the necessity for a larger addition of water. According to the valid standards for concrete screed related to the frost resistance, it could be concluded that maximal suitable cement replacement contents are 12.5, 37.5 and 50 wt.% for ceramic powder, fly ash and blast furnace slag, respectively. The freeze-thaw resistance of the studied materials was found to be strongly related to the content of CSH and CAH hydrates.
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Walotek, Konrad, Joanna Bzówka, and Adrian Ciołczyk. "Impact of Shredded Rubber Waste (SRW) on the Range of Elastic Work of Road Construction Mixtures Containing Industrial Waste Bound with a Binder." Materials 15, no. 23 (November 29, 2022): 8503. http://dx.doi.org/10.3390/ma15238503.
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The paper presents the results of research on a composite mixture intended for use in road construction. The purpose of developing the mixture is to be able to use large amounts of industrial waste to produce building material. The waste used are coal slate from the mining industry, shredded rubber waste from used passenger car tires and fly ash from power plants. The mixture (SRFC) consists of unburnt coal-mining slate (S), shredded rubber waste (R), fly ash (F) and cement(C). A test under cyclic loading conditions was carried out on samples prepared from the SRFC mixture, in which the global deformations and local strains caused on the samples were measured. A measurement system using digital image correlation was used for the research. On the basis of the conducted research, it was found that the content of shredded rubber waste significantly influences the deformability of the tested mixtures and allows for the extension of the scope of elastic deformation in which the tested samples work.
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Stehlík, Dušan, Petr Hyzl, and Michal Varaus. "Waste Building Materials to Roads in Czech Republic." Applied Mechanics and Materials 832 (April 2016): 10–17. http://dx.doi.org/10.4028/www.scientific.net/amm.832.10.
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Using waste building materials in pavements is one of the goals of transportation sustainable development in the Czech Republic. As part of research projects of the Technology Agency of the Czech Republic, a project was devised, which focused on maximal utilization of waste building materials when constructing pavements. After the initial verification of properties of the recycled aggregate (especially concrete waste building material), the research focus shifted towards the utilization of these waste building materials in cement bound granular mixtures.
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Tereshchenko, Tatiana, and Serhii Illiash. "CLASSIFICATION AND APPLICATION OF SOILS STABILIZED WITH HYDRAULIC BINDER IN ACCORDANCE WITH EUROPEAN STANDARDS." Avtoshliakhovyk Ukrayiny, no. 1 (261)’2020 (March 20, 2020): 40–48. http://dx.doi.org/10.33868/0365-8392-2020-1-261-40-48.
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Soils being the most widely used materials for road building industry predominantly contribute the improvement of their mechanical and/or technological properties. Relating to the world-wide experience in road building industry, the most effective method for such improvement is treatment of soils with hydraulic binder under optimum water content. Those mixtures being properly compacted set and harden by hydraulic reaction and give stabilized soils. Requirements and classification of hydraulically stabilized soils established by European standards provide wide possibilities for soils application considering their performance in pavement layers. The elaboration of Ukrainian standards identical to the European standards relating hydraulically stabilized soils should permit the elongated life cycle of pavement and also decrease expenses on repairs of road pavements caused by deformation of sub-grade. This article reviews classification and application of hydraulically stabilized soils according to the requirements of European standards. In accordance with European standards, stabilized soils are classified as hydraulically bound mixtures which properties are covered by Specifications on Hydraulically Bound Mixtures (European Standard EN 14227, Part 15). To conform the standard requirements soils should be treated by standard hydraulic binder (or a combination thereof): cement, slag, fly ash, lime, or a standard hydraulic road binder should be applied. Composition and methods of manufacturing (compaction) of specimens of hydraulically stabilized soils give several strength classes of stabilized materials with the highest category characterized by the cubes compressive strength not less than 12 MPa. European standards establish also classification of hydraulically stabilized soils by tensile strength Rt in combination with elastic modulus E; according to that classification the stabilized materials are divided into five categories from T1 to T5. European standards establish also classification of fresh mixtures by immediate bearing index. This value determines the suitability of a compacted layer to support the immediate trafficking. Nevertheless, that requirement may not cover cement-stabilized mixtures for construction of layers which are not intended to be trafficked for 7 days. The in-situ manufacture of stabilized mixtures needs some measures to minimize the inadequacy of properties of a material, or geometry of a layer such as an increased proportion of a binder or an increased layer thickness. Keywords: hydraulically stabilized soils, classification, compressive strength, immediate bearing index, construction of a layer.
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Farhan, Ahmed Hilal, Andrew Dawson, and Nick Thom. "Behaviour of rubberised cement-bound aggregate mixtures containing different stabilisation levels under static and cyclic flexural loading." Road Materials and Pavement Design 21, no. 8 (April 24, 2019): 2282–301. http://dx.doi.org/10.1080/14680629.2019.1605924.
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Strangfeld, Christoph, and Tim Klewe. "Comparison of the Calcium Carbide Method and Darr Drying to Quantify the Amount of Chemically Bound Water in Early Age Concrete." Materials 15, no. 23 (November 26, 2022): 8422. http://dx.doi.org/10.3390/ma15238422.
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Hydration is the exothermic reaction between anhydrous cement and water, which forms the solid cement matrix of concrete. Being able to evaluate the hydration is of high interest for the use of both conventional and more climate-friendly building materials. The experimental monitoring is based on temperature or moisture measurements. The first needs adiabatic conditions, which can only be achieved in laboratory. The latter is often measured comparing the weight of the material sample before and after oven drying, which is time-consuming. This study investigates the moisture content of two cement-based and two calcium sulphate based mixtures for the first 90 days by using the calcium carbide method and oven drying at 40 °C and 105 °C (Darr method). Thereby, the amount of chemically bound water is determined to derive the degree of hydration. The calcium carbide measurements highly coincide with oven drying at 40 °C. The calcium carbide method is therefore evaluated as a suitable alternative to the time-consuming Darr drying. The prompt results are seen as a remarkable advantage and can be obtained easily in laboratory as well as in the field.
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Hájek, Matej, Martin Decký, and Walter Scherfel. "Objectification of Modulus Elasticity of Foam Concrete Poroflow 17-5 on the Subbase Layer." Civil and Environmental Engineering 12, no. 1 (May 1, 2016): 55–62. http://dx.doi.org/10.1515/cee-2016-0008.
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Abstract Principles of sustainable development create the need to develop new building materials. Foam concrete is a type of lightweight concrete that has many advantages compared to conventional building materials, for example low density and thermal insulation characteristics. With current development level, any negatively influencing material features are constantly eliminated as well. This paper is dealing with substitution of hydraulically bound mixtures by cement foam concrete Poroflow 17-5. The executed assessment is according to the methodology of assessing the existing asphalt pavements in Slovak Republic. The ex post calculation was used to estimate modulus range for Poroflow 17-5 based on the results of static load tests conducted using the Testing Experiment Equipment.
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Vdovin, E. A., and V. F. Stroganov. "Modification of cement-bound mixtures with sodium formate additives for the construction of pavement bases at low air temperatures." IOP Conference Series: Materials Science and Engineering 786 (March 31, 2020): 012065. http://dx.doi.org/10.1088/1757-899x/786/1/012065.
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Gołos, M. "Mechanically stabilised layer by geogrids in road construction as an environmental aspect of sustainable development." IOP Conference Series: Materials Science and Engineering 1260, no. 1 (October 1, 2022): 012023. http://dx.doi.org/10.1088/1757-899x/1260/1/012023.
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Abstract The purpose of this paper is to focus on the advantages of environmental aspects of mechanically stabilised layer by using geogrids (MSL). MSL is utilised in road construction as a sub-base layer or capping layer for a week sub-soil improvement. The concept of a MSL says that unbound granular layer is stabilized by the non-reinforcing hexagonal geogrid by the way of interlock with the aggregate. The mechanism of interlock means that both geogrid and aggregate interact under applied external load. The beneficial consequence on the serviceability of that layer by the resisting of the movement of the particles is defined as stabilisation. Mechanically stabilised layer by geogrid allows to save both money and time of construction compared to traditional technologies. Moreover, it also substantially supports sustainable development being a successful alternative to traditional solutions in road construction, such as: soil replacement, cement and other hydraulically bound mixtures or granular unbound layers which are non-stabilised by geogrids. MSL gives massive benefits for the environment, allowing for significant reduction of energy usage and greenhouse gases emission (mainly CO2). The paper shows the methodology of carbon footprint approach, which is an equivalent amount of CO2 emission, resulting from all component processes related to a specific technology used in road construction.This paper describes also the basic rules of how to calculate the amount of this reduction by using a special tool, so called Carbon Calculator (CC) designed by one of the leading geogrid manufacturer. CC allows to determine the reduction of CO2 as a result of geogrid utilisation in MSL compared to other well-known and long-standing solutions, mainly traditional granular unbound and cement or other hydraulically bound mixtures. A number of calculations of carbon footprint with MSL and other traditional solutions used as a sub-base or capping layer in the road construction have been done and the results of them have been presented in the further part of this article.